Plural independent signal producing hydraulic governor



J. HORSCH June 17, 1969 PLURAL INDEPENDENT SIGNAL PRODUCING HYDRAULIC GOVERNOR Sheet Z of 2 Filed Sept. 20, 1966 INVENTOR. JOACHIM HORSCH ATTORNEYS GOVERNOR SIGNAL PRE SSURE June 17, 1969 J. HORSCH 3,450,144

PLURAL INDEPENDENT SIGNAL PRODUCING HLYDRAULIC GOVERNOR Filed Sept. 20, 1966 Sheet 2 of 2 38 285- E 26 32 f m 0 s1 UPSHIFT A PSI DOWNSHIFT INVENTOR.

e s IO I2 I4 l6 I820 2 TRANSMISSION OUTPUT RPM (X I00) JOACHIM HORSCH ATTORNEYS United States Patent US. Cl. 137-54 2 Claims ABSTRACT OF THE DISCLOSURE A centrifugal force hydraulically operated governor produces a plurality of independent signals in response to rotational speed wherein each signal produced can be utilized to provide a pressure-speed curve the pressure value of which extends over the same range for each curve.

This invention relates to a centrifugal force operated hydraulic governor. The invention further relates to a governor capable of producing a plurality of independent signals in response to rotational speed. More particularly the invention relates to a centrifugal force operated hydraulic governor wherein each signal produced can be utilized to provide a pressure speed curve whose pressure value extends over the entire range of hydraulic pressure available to the governor system. As a result of this unique governing feature, the rate of change of pressure with respect to rpm. is optimized over a large speed range. Adequate pressure signals are made available covering a wide speed range while maintaining a much lower pressure range than was heretofore possible. Moreover, much more flexibility is provided with respect to the production of the desired speed sensitive signals since each pressurespeed curve provides the full range of pressure values available to the system and can be individually adjusted to meet requirements of particular portions of speed range.

In addition to the above, it is an object of the invention to provide a hydraulic governor that is particularly adapted for use as a speed responsive control of a hydraulically controlled motor vehicle power transmission unit such as described in assignees co-pending US. patent application Ser. No. 580,693, filed Sept. 20, 1966, and entitled Automatic Transmission Control.

It is another object of the invention to provide an improved hydraulic governor of simplified construction and easy assembly which eliminates the use of springs and other critical tolerance elements.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what is now considered to be the best mode contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawing:

FIG. 1 is a longitudinal sectional view of a governor device according to the invention;

FIG. 2 is a cross-sectional view taken on the line IIH of FIG. 1;

FIG. 3 is an end view taken on the line IIIIII of FIG. 1; and

FIG. 4 is a graph depicting a plurality of governor pressure curves produced by a governor embodying the invention.

Referring now to FIGS. 1 and 2, the basic component Patented June 17, 1969 of the governor comprises a cylindrical housing 10 which is supported through bushings 12, 13 and 14 by a fixed stub shaft 16. The cylindrical housing 10 is attached to rotatable adapter 18 by bolts .19 or the like. The adapter 18 is provided with a gear 20 integrally formed thereon which meshes with an idler gear 22. The idler gear 22 is driven by a gear (not shown) which latter gear is driven from the output shaft of a motor vehicle power transmission unit. Formed in the housing or valve body 10 are a plurality of bores 26. Each bore 26 slidably receives a spool 28a, 28b and 280 for relative radial movement therein. Each of spools 28a, 28b and 28c is of the same general configuration but of difi'erent weight or mass and having different reaction areas so as to move radially out wardly to regulate different pressure levels due to the centrifugal force created upon rotation of the housing 10. Each spool has an external annular groove 30 which communicates via port means 34 with an internal cavity 32 formed therein. The radially outermost portion of each bore 26 contains an insert 38 which is retained in place by a snap ring 40. The cavities 32 of spools 28a and 28b are closed off at their radially outer ends by means of reaction plungers 42 which are bottomed against their respective inserts 38. Such a reaction plunger could also be provided for spool 280 but in the preferred embodiment the fluid pressure in cavity 32 thereof reacts directly between spool 28c and insert 38 which seals off the end of bore 26. The mass of the various spools may be more finely adjusted by means of removable washers 46 which are held in place by snap rings 47.

As shown, stub shaft 16 is fixed to a manifold 23 which has an internal conduit 24 associated therewith. The conduit 24 communicates with a conduit 25 formed intern-ally of the stub shaft 16 so that a substantially constant pressure fluid, herein denoted line pressure, can be supplied to the plurality of valve bores 26. The line pressure communicates with valve bores 26 by way of annular groove 48, bushing holes 49 and pressure fluid inlets 50. Thus, when the valve spools move radially outward, from the position shown, line pressure flows into valve groove 30 where it .can communicate with both a pressure fluid outlet 51 and the valve spool cavities 32 (via port 34). Correspondingly, when the valve spools move radially inwardly the fluid pressure in spool cavities 32 may communicate through port 34 and groove 30 with a vent or exhaust area 53. It should be noted that each of the fluid outlet passages 51 extends through body member I10 to one of the annular grooves 55 which communicates through one of the bushing ports 57 with one of the plurality of bores 59 formed in the downstream end of stub shaft 16.

As shown in FIGS. 1 and 3, each bore 59 communicates with a line 61 suitably fitted into an adapter 63 which adapter is bolted or otherwise secured to frame member 65 by fastening means 67. Each of the lines 61 leads to a particular pressure sensitive fluid operated device, such as a transmission selector valve (not shown). The combination of the governor and selector valve gives a system responsive to the rotational speed of the transmission output shaft.

The manner in which the aforedescribed device functions as a hydraulic governor will now be described. The manifold conduit 24 is connected to some source of pressurized fluid which may be from the transmission controls or in the case of a motor vehicle power transmission unit is usually a pump driven by the transmission input and/ or output shafts. Conduit 24 is thus usually pressurized with a pressure fluid of substantially constant pressure regardless of the operating speed of the associated pump. In any event, fluid under pressure is directed through passage 24 into passage 25- of the stub shaft 16. From passage 25 it flows into the annular groove 48 through holes 49 of the bushing 13 into fluid inlet passages 50 which communicate with the valve bores 26. As the governor body rotates, the centrifugal force on valves 28a, 28b and 280 will cause them to progressively move outwardly which movement will open fluid inlets 50 to annular grooves 30 so that pressure fluid will be directed through ports 34 of the valve spools and thence into the respective spool cavities 32. A force equilibrium on the spools will be established such that the pressure in the respective cavities 32 multiplied by the reaction area of the particular plunger 42 (insert 38 in the case of valve spool 28c) is equal to the centrifugal force acting on the valve spool in question. Thus a metering condition exists between the supply pressure in fluid inlet 50, the pressure in the particular spool cavity 32 and the exhaust area 53 such that the pressure in a given cavity 32 is between the supply pressure in passage 50 and the exhaust pressure in the area 53. As a result, the pressure in any given spool cavity 32 is a function of the rotational speed of the transmission output shaft (centrifugal force) and fixed design parameters of the particular valve spool such as its size, weight, reaction area, etc.

As the speed of the transmission output shaft (not shown) and consequently the speed of the governor body increases, centrifugal force tends to progressively urge the valve spools radially outwardly to a position wherein the valve groove 30 has cleared the edge of fluid inlet 50. At this time line pressure fluid in fluid inlet 50 can pass into the spool cavity 32 and react upon the said spool. The radially directed force acting on the spool, resulting from the admittance of pressure fluid to the spool cavity 32, tends to urge the spool radially inwardly towards stub shaft 16 and to thereby close off the pressure fluid supply from. fluid inlet 50. However, at the same time that the unbalanced pressure fluid generated force in the cavity portion 32 is urging the spool to a position to close off fluid inlet 50, there is a simultaneously applied centrifugal force acting on the spool, due to rotation of the governor body 10, which force tends to move the valve spool radially outwardly and open the fluid inlet 50 for fluid communication with the spool cavity 32.

It will thus be seen that radial movement of any one of the plurality of valve spools is the resultant of two simultaneously acting, opposed, radially directed forces that cause the particular spool to function as a pressure regulating valve. The spool reciprocates radially until an equilibrium is established between the forces acting thereon for each speed of the transmission output shaft. When the several applied forces are in equilibrium then the valve spools are positioned as shown in FIGS. 1 and 2. At the time the valve spool is in equilibrium the pressure of the fluid in cavity 32 is directly proportional to the speed of the transmission shaft and this pressurized fluid in cavity 32 and outlet conduits 51, 59 and 61 is denoted governor pressure. As previously noted, this governor pressure can be used to operate any sort of pressure responsive device resulting in a shaft speed responsive system.

It will be seen that when the transmission output shaft reaches a predetermined speed, the speed of rotation of housing will create a predetermined centrifugal force on valve spool 28a which will produce a predetermined governor pressure in the cavity 32 associated therewith. This governor pressure will be reflected through the fluid outlet passage 51 associated with spool 28a and hence through one of the lines 61 to a transmission selector valve (not shown) causing said valve to automatically shift the transmission into a higher speed range. As the transmission output shaft continues to increase in speed, pressure, regulated by valve spools 28b and 280, will rise to levels which will cause their respective selector valves to shift at preset shift points as determined by the selector valve design. Conversely, as the vehicle begins to slow down, either from load or a decrease in engine speed from the operators control, the pressure in the cavities of the respective valve spools will overcome the resulting decrease in centrifugal force on them, such that the pressure to the selector valves will drop sufficiently to cause the transmission to shift to a lower speed range.

FIG. 4 is a graph which reflects three different governor pressure curves A, B and C produced respectively by the valve spools 28a, 28b and 280. As indicated by the curve A, valve 28a produces a signal pressure ranging from 0 to p.s.i. at approximately 491 r.p.m. of transmission output speed. This signal, when read by its respective selector valve or valves, will cause the transmission to upshift from second to third gear as the speed increases to approximately 340 r.p.m. and to upshift again from third to fourth as the speed increases to approximately 491 r.p.m. and so on for each governor curve B and C until the transmission is in its highest possible range. As described above, as the transmission output shaft begins to decrease in speed and the signal pressure to each selector valve begins to drop the transmission will shift down inversely from the upshift pattern.

As shown by the graph of FIG. 4, the use of a governor having multiple valve spools as disclosed herein provides optimum pressure-speed curves in the gear shifting ranges wherein a small change in r.p.m. value results in a relatively large change in pressure value. As a result, the particular pressure responsive means controlled by the governor may be less sensitive. For example, where the governor is used to control transmission shift points, as previously described, less sensitive selector valves are required to sense the change in pressure which ultimately results in a transmission shift.

Moreover, it will also be noted from viewing curves A, B and C of FIG. 4 that all upshift and downshift points, respectively, occur at approximately the same pressure value although the r.p.m. value increases markedly from curve A to curve C for each shift point. The removable washers 46 make it possible to provide a fine adjustment permitting such shift points to occur at substantially the same pressure value on each of the curves A, B, and C. This feature provides an important advantage where the governor is used to regulate transmission shifts since it decreases the number of different selector valves required for shifting the transmission. Such a feature is particularly useful in multirange transmissions, many of which have six to eight speed ranges.

I claim:

1. A centrifugal force hydraulically operated governor for producing a plurality of independent signals in response to rotational speed, wherein each signal produced can be utilized to provide a pressure-speed curve the pressure value of which extends over the same range for each curve, said governor adapted to be mounted on a rotatable member and comprising:

a valve body provided with a plurality of radially outwardly extending bores;

a movable spool mounted in each of said bores for relative radial movement therein;

each of said spools having an internal cavity formed therein;

port means formed in each spool for communicating each spool cavity with its respective bore;

fixed reaction means adapted to close off the radially outer end of each said spool cavity to form a pressure reaction area with respect thereto;

a pressure fluid inlet to each of said bores, each pressure fluid inlet communicating common pressure fluid of the same pressure value to said bores;

each said bore having an independent pressure fluid outlet;

each said spool being arranged in said bore to reciprocate across said pressure fluid inlet and control 5 6 the admission of pressure fluid to said bore and claim 1 wherein each said spool is provided with resaid spool cavity; movable means for varying the mass thereof. each said spool cavity having a shape which cooperates with said reaction means to provide an unbalanced References Clted area upon which the pressure fluid admitted to said 5 UNITED STATES PATENTS cavity reacts to urge said spool radially inwardly 2 73 5 3/1956 M Af 5 in opposition to the outwardly directed centrifugal 2,741 256 4 195 Barton 137 55 forces exerted on the spool due to rotation of said 2,938,502 5/1960 N l 137.46v X rotatable member; 2,941,539 6/1960 Hewko 137-56 each said spool having differing design parameters for 10 3,194,252 7/1965 Locher 137-56 X producing a differing predetermined pressure in the 3,196,889 7/1965 Hims 137-56 cavity of said spool in response to a predetermined 3, ,77 12/1965 LOndal 137-56 X rotational velocity of said rotatable member; and, vent means connected to each said bore and arranged 15 CLARENCE GORDON, Pnmary Examine"- to be controlled by radial movement of said spool. US. Cl. X.R. 2. A hydraulically operated governor as set forth in 137-56 

